Answers for "how to update existing heroku app"

heroku and github on termi

$ heroku git:remote -a thawing-inlet-61413
set git remote heroku to https://git.heroku.com/thawing-inlet-61413.git

how to update heroku

heroku update
#(OR)
sudo apt update && sudo apt install heroku
# to update heroku

heroku and github on termi

$ git remote rename heroku heroku-staging